class User():

    def __init__(self, first_name, last_name):
        self.first_name = first_name
        self.last_name = last_name

    def describe_user(self):
        print('first_name: ' + self.first_name +
              ',last_name: ' + self.last_name)

    def greet_user(self):
        print('你好：' + self.first_name + ' ' + self.last_name)


user_a = User('cheng', 'xiaoqi')
user_a.describe_user()
user_a.greet_user()
